add date with start of memo writing

personal_vm/personal_vm.poly.pm

@@ -2,6 +2,7 @@
 
 ◊title{Personal Computing with VMs}
 ◊author{George C. Privon}
+◊start-date{2020-05-13}
 
 ◊tags{computing, virtual machines}
 ◊; from https://www.gwern.net/About#confidence-tags

template.poly.pm

@@ -2,6 +2,7 @@
 
 ◊title{Memo Template}
 ◊author{George C. Privon}
+◊start-date{2020-05-13}
 
 ◊tags{}
 ◊; from https://www.gwern.net/About#confidence-tags